Comprehensive utilization method for separating, concentrating and purifying manganese sulfate, magnesium sulfate and calcium sulfate in high-salt waste water

Abstract

The invention relates to a comprehensive utilization method for separating, concentrating and purifying manganese sulfate, magnesium sulfate and calcium sulfate in high-salt wastewater. The temperature of the wastewater mother liquor is kept at 50-60°C, and the pH value of the wastewater is adjusted to 10-10.5 with ammonia water or liquid ammonia. First, the manganese ions and magnesium ions in the wastewater are separated in the form of manganese hydroxide and magnesium hydroxide, and then the separated manganese hydroxide and magnesium hydroxide are added with sulfuric acid to prepare manganese sulfate and magnesium sulfate solutions, and the separated Separation is realized by evaporation and crystallization to produce manganese sulfate monohydrate and magnesium sulfate hexahydrate; the waste water of separated manganese hydroxide and magnesium hydroxide is added with milk of lime to adjust the pH value, calcium sulfate crystals are precipitated, and dihydrate is produced after pressure filtration Calcium sulfate. The wastewater treated by the invention reaches the discharge standard, and can be discharged outside or reused inside the enterprise, and all solid wastes in the wastewater can be recycled and utilized. The investment of the invention is relatively low, and the annual net return on investment is more than 15%.

Description

technical field [0001] The invention belongs to the chemical industry fields such as manganese chemical industry and vanadium chemical industry and the field of waste water treatment and production in heavy metal extraction in metallurgical industry, and specifically relates to the step-by-step process of manganese sulfate, magnesium sulfate and calcium sulfate in high-salt waste water containing manganese sulfate, magnesium sulfate and calcium sulfate Separation, concentration crystallization, purification and wastewater recycling methods. Background technique [0002] In the process of preparing qualified manganese sulfate electrolyte in electrolytic manganese enterprises, and in the process of calcification and roasting in vanadium chemical enterprises to produce vanadium oxide, most of them will produce high-salt wastewater containing manganese sulfate, magnesium sulfate and calcium sulfate, of which Mn 2+ The content is 10-20g / L, Mg 2+ Content in 1-3g / L, Ca 2+ The con...

AI Technical Summary

Problems solved by technology

For the separation of manganese sulfate, magnesium sulfate, and calcium sulfate, the treatment method of most enterprises at present is to first use milk of lime to precipitate manganese sulfate, magnesium sulfate, and calcium sulfate together, and then discharge the waste water or try to reuse it. Manganese sulfate, magnesium sulfate, and calcium sulfate cannot be separated, which not only wastes resources, but also makes it difficult for the treated wastewater to meet the discharge standards

Some companies have also proposed the method of manganese sulfate electrolysis after calcium removal, but due to the high content of magnesium sulfate in wastewater, the power consumption of electrolysis is greatly increased, and the concentration of manganese sulfate is too low, which is far from meeting the concentration requirements of qualified electrolyte. There is also a large amount of calcium ions, so it is impossible to pass through, and the cost is high, and the gain outweighs the gain

There are also some manganese sulfate production enterprises. Although calcium and magnesium are removed from manganese sulfate, a considerable part of manganese sulfate is lost, and the separated calcium and magnesium are also wasted.

With the implementation of new standards for environmental protection and energy conservation, and the intensification of supervision, it is difficult to discharge this type of wastewater up to standard, especially because resources cannot be comprehensively utilized

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